1. Field of the Invention
The present invention relates to machine-tools and more particularly, to the arrangement of functional parts of a machine-tool for high speed machining to ensure handling and maintenance under the best conditions.
2. Discussion of Background
High speed machining generally takes place using a tool rotatably driven by the motor driven axis of an electric spindle installed in a ram, wherein the ram is mounted to be movable along X-, Y-, and Z-axes, which are mutually perpendicular to each other.
A machine-tool is typically provided with four main working stations, which are:
(1) an actual machining station, including the machine-tool, driven rotationally by the motor driven axis of the electric spindle, wherein the machine-tool shapes the workpiece to be machined;
(2) a driving station situated up-line (or upstream) from the machining station, wherein the driving station is made up of a group of devices that ensure, in particular, X-, Y-, and Z-axes movements of the ram of the electric spindle, as well as feeding of the electric spindle for the rotation of the electric spindle's tool carrier axis;
(3) a control station operating together with the driving station, wherein the control station functions by using a program of pre-established instructions to take charge of the different stages of machining of the workpiece; and
(4) a magazine for storing tools in order to keep the machine-tools, to be used in the machining process, near the machining area, during the different stages of machining of the workpiece.
The machining station includes the machine-tool and electric spindle for machining the workpiece, wherein the machine-tool is driven by the motor driven axis of the electric spindle, which is fed by electric cables coming from the control station. The electric spindle is housed in a ram, which is movable in the X-, Y-, and Z-axes directions.
The driving station includes all of the motor elements to ensure the X-, Y-, and Z-axes movements of the ram.
The control station is connected to an electric group and a hydraulic group, as necessary, in order to distribute electric and hydraulic power, respectively, and to ensure control of the components using the electric and hydraulic power, respectively.
The function of the machine-tools is to machine the workpiece, in a minimum of time and with a maximum of precision. The shape of the workpieces to be machined is becoming more and more complex, thus requiring the use of several tools, from the nearby tool magazine, or even several machine-tools to ensure complete machining of the workpiece. A configuration including several of the machine-tools taking part in the machining of the same workpiece is called a "machine transfer." A "machine transfer" can become a "flexible workshop" to ensure the complete machining of several different workpieces. A "machine transfer" is a group of machine-tools which are placed perpendicular to the production line of the workpiece to achieve all the machining stages of that workpiece. Such an installation takes place with respect to limiting factors, namely, the dimension of the machine-tools and especially, the floorspace available for the machine-tools. It is therefore essential, for reasons of cost and space taken up, that the machine-tools be compact in order to enable the installation of a "flexible workshop" or a "machine transfer." In fact, a principal disadvantage of conventional machine-tools is that they take up a very large amount of floorspace, despite the miniaturization of the components that can presently be achieved. The size of the machine-tool corresponds, first of all, to the machining to be done. In other words, to have a machine-tool that can be flexible, it has to adapt to all machining types and to all dimensions. In any case, the electric spindle needs to be of large dimensions to ensure a high speed of rotation or a large engine power to enable the use of machine-tools of large dimensions. This leads to important dimensions of the ram and consequently, important dimensions of the motor elements to ensure the ram's movements in X-, Y-, and Z-axes directions. In the field in which the present invention applies, the machine-tools are of very large dimensions, so that the users lacking sufficient floorspace to house a machine-tool, must undertake extensions to their premises. This puts a considerable strain on the cost of installing there machine-tools, in addition to the actual cost of the machine-tools.
Another disadvantage of the machine-tools for high speed machining is the fact that it is necessary to authorize access to all the functional parts or components of the machine-tool to ensure adequate maintenance thereof. As a result, access areas which permit an operator to ensure the maintenance of the vital part of the machine-tool, in particular, access areas of the driving station, must be provided around doors, hatches, or windows. The doors, hatches, or windows were conceived to authorize maintenance of the machine-tool, but increase the floorspace needed to set up each machine-tool. In "machine transfers," even more floorspace is needed, so that not only the amount of floorspace needed to install the machine-tool is increased, but the number of conveyors conveying the workpieces from one machine-tool to another is increased as well.
Another disadvantage of the machine-tools for high speed machining is that they require the presence of a cooling group. In fact, the functioning of the machine-tools raises the temperature of the workpieces at the driving station to a level which would be detrimental for the lifespan of the workpieces, if subsidiary cooling was not set up. This rise in temperature could also lead to the dilatation of the parts of the driving station, which would have as a consequence thereof, a non-negligible loss of precision in the machining of workpieces. The cooling groups are generally of large dimension and are difficult to integrate into the machine-tools.
Starting with these considerations with respect to the original configuration of a machine-tool, applicant has attempted to reduce the floorspace requirement of the machine-tool, while making it easier to access the vital parts for handling, replacement, repair, etc. The configuration of the machine-tools of the present invention rests on a flexible ergonomic arrangement of the functional parts thereof, while avoiding the disadvantages described above with respect to conventional machine-tools.